Process of manufacturing nitrated cellulose.



UNITED STATES PATENT OFFICE.

ADOLF VOIGT, OF SOHClNBECK-ON-THE-ELBE, GERMANY.

PROCESS MANUFACTURING NITRATED CELLULOSE.

Specification of Letters Patent.

Patented July 23, 1907.

Application filed March28,1904. Serial No. 200,348.

gun-cotton or collodion wool the following process has been hitherto -used. The scoured and dried cotton fibers are brought into a mixture of nitric acid and sulfuric acid. Thereafter the product is ireedfrom the acid by means of along and complicated boiling, washing and grinding process. The so obtained nitro cellulose has the structure of the raw fiber and muststill be subjected to a diluting and gelatinizing process in order to make the nitro cellulose fit for the manufacture of a blastingmaterial.

It has been tried to simplify the nitrating and pulverizingprocess for instance by combining both processes, so

as to be carried out by one operation, or by efie'cting the pulverization'beiore the nitrification. The latter trials have been made for the purpose oiobtaining a highly nitrated product of a uniform composition. According to another process the cellulose Has been dissolved in suitable liquids, then it has been decanted, washed and dried, whereaiter the so-obtained powdered mass has been nitrated. In addition to being very complicated and expensive, this process has the disadvantage that a powdered material is very hard to nitrate and afterwards to wash out, and the stability of the nitro products so obtained is usually not suflicient in practice.

All the disadvantages above mentioned are overcome by the process forming the subject of the present invention, which process is carried out as follows: The scoured and cleaned cotton or cellulose is brought into concen- -trated sulfuric acid having a temperature of about 2 or 3 centigrade. Thereafter the material is stirred up, until it forms a pulpy mass. It has proved advantageous to use about 1 kg. of cellulose for 5kg. of concentratedsulfuric acid. The disintegration of the fibers takes place very rapidly with a simultaneous increasing of the temperature. The operation is therefore advantageously carried out with a simultaneous cooling of the materials. -A.iter the structure has been destroyed, about 2 kg. of concentrated nitric acid are added, thereby converting the pulpy nitro-product into hard balls or lumps. Also during the latter operations the materials are advantageously cooled. After about 2 or 3 hours the mass is congealed and forms a solid cake, which is washed out United States is:

in great quantities of water, advantageously in a filtering press.

The obtained product after drying has the form of a very fine powder of a great stability} It does not explode by shocks or friction or by the blow of a hammer, I

even when upon an iron plate. When ignited it burns with a relatively small velocity. It can be exposed for more than one hour to a temperature of 135 degrees centigrade without igniting.

The material has proyed very advantageous for the manufacture-oi shooting and blasting powders, of var nishes and the like.

Having thus fully described the nature of my invention, what I desire to secure .by Letters Patent oi the 1. Process of manufacturing nitrated cellulose, con

sisting in' introducing ceilulose-fibers into concentrated sulfuric acid of a low temperature, leaving the same there intill the disintegration of the fibers has taken place, so as to form a pulpy-inass, and then adding to this pulpy mass a suflicien't quantity of concentrated nitric acid toform a nitrating mixture, whereby the disintegrated pulp is nitrated and converted into hard balls or lumps, and then washing the nitro-cellulose after being congealed in water.

2. Process of manufacturing nitrated cellulose, consist ing in introducing cellplose-iihers into concentrated sul furic acid of about 2 or=3 degrees centigrade, leaving the same therein till the disintegration of the fibers has taken place, so as to form a' pulpy mass, and then adding to this pulpy mass a'suflicient quantity of concentrated nitric acid to form a nitratingmixture, 'whereby the disinte: grated pulp is nitrated-and converted'into hard ballsfor lumps, and then washing the nitro-cellulose after being congealed in water.

3. Process of manufacturing nitrated cellulose, consisting in introducing cellulose fibers into concentrated sul-f {uric acid of about 2 or 3 degrees centigrade, leaving the same therein; till the disintegration of the fibers has taken place; cooling the mass while the reaction takes place, so as to form a pulpy mass, and then adding to this pulpy mass :1 sufli cient quantity of concentrated nitric acid to form a nitrnting mixture, whereby the disintegrated pulp is nitrated and converted into hard balls or lumps, cooling the mixture while this reaction ta'kes'pla'ce, and then washing thenitro-cellulose after being congealed in water. 4. Process of manufacturing nitrated cellulose, consist ing in introducing cellulose fibers into concentrated sulfuric acid of about2 or 3 degrees centigrade, the ratio of these two substances being about 1 kg of cellulose to- 5 kg of concentrated sulfuric acid, leaving the cellulose fibers in the sulfuric acid, till the disintegration o! the fibers has taken place, then adding to this pulpy mass about 2 kg of concentrated nitric acid and then washing the nitro-cellulose after being congealed in water.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

' ADOLF VOIGT.

Witnesses:

SARAH C. McKsLL P, JAMES L. A. Bunnnnn. 

